Lubricant for transport of P.E.T. containers

Abstract

The invention relates to compositions, methods and processes of dilutable aqueous conveyor lubricant concentrates and to the use of the lubricant compositions especially as lubricants for the transport of P.E.T. containers, i.e., containers made of ethylene terephthalate homopolymers, copolymers and mixtures thereof. The aqueous lubricant concentrate compositions (pH 9.0-10.5) contain fatty acid, alkyl phosphate ester and alkyl aryl phosphate esters, which serve the dual role as emulsifying agent and stress crack inhibitor, in the presence of potassium hydroxide as the saponifying agent and in combinations with typical coupling/hydrotrope and chelating agents; and optional inorganic phosphate.

What is claimed is: 
     
       1. An aqueous conveyor lubricant concentrate capable of being diluted with water for applying to the exterior of P.E.T. containers being transported along a conveyor system comprising: (a) a long chain fatty acid;   (b) emulsifying agent;   (c) stress crack inhibiting agent; which is an alkyl aryl phosphate ester or an alkyl phosphate ester;   (d) saponifying agent;   (e) sequestrant;   (f) coupling agent/hydrotope;   (g) water; and   (h) optionally, an inorganic phosphate wherein the pH of said concentrate is in the range of 9 to 10.5.     
     
     
       2. The aqueous conveyor lubricant concentrate of claim 1 wherein the saponifying agent is an alkali metal hydroxide. 
     
     
       3. The aqueous conveyor lubricant concentrate of claim 1 wherein the stress crack inhibiting agent is an alkyl aryl phosphate ester having between eight and ten carbon atoms in the alkyl portion. 
     
     
       4. The aqueous conveyor lubricant concentrate of claim 1 wherein the stress crack inhibiting agent is an alkyl phosphate ester. 
     
     
       5. The aqueous conveyor lubricant of claim 1 wherein the stress crack inhibitor, which also serves as an emulsifying agent, is selected from a group consisting essentially of polyoxyethylene decyl ether phosphate, polyoxyethylene nonylphenyl ether phosphate, polyoxyethelyene dinonylphenyl ether phosphate, and mixtures thereof. 
     
     
       6. The aqueous conveyor lubricant concentrate of claim 1 wherein the emulsifying agents are the alkyl phosphate ester, alkyl aryl phosphate ester, alkyl aryl ethoxylate, alkyl ethoxylate and mixtures thereof. 
     
     
       7. The aqueous conveyor lubricant of claim 1 wherein the emulsifying agents are selected from a group consisting essentially of polyoxyethylene decyl ether phosphate, polyoxyethylene nonylphenyl ether phosphate, polyoxyethylene dinonylphenyl ether phosphate, ethoxylated nonylphenol, ethoxylated dinonylphenol, and ethoxylated tridecyl alcohol, and mixtures thereof. 
     
     
       8. The aqueous conveyor lubricant of claim 2 wherein the alkali metal hydroxide is potassium hydroxide. 
     
     
       9. The aqueous conveyor lubricant of claim 1 wherein the concentrate comprises: (a) from about 0.25 to 25 percent, by weight of the emulsifying agent;   (b) from about 0.10 to 15 percent by weight of the stress cracking inhibitor;   (c) from about 0.5 to 40 percent, by weight, of the long chain fatty acid;   (d) from about 0.2 to 15 percent, by weight, of the saponifying agent;   (e) from about 2 to 25 percent, by weight, of the sequestrant;   (f) from about 1 to 35 percent, by weight, of the coupling/hydrotrope agent;   (g) from about 5 to 80 percent, by weight, of the water;   (h) optionally, from about 0.10 to 12 percent, by weight, of the inorganic phosphate.   
     
     
       10. The aqueous lubricant concentrate of claim 9 wherein the concentrate has the pH between 9.0 and 10.5. 
     
     
       11. A method of inhibiting stress cracking in P.E.T. containers comprising the step of applying a dilute aqueous fatty acid soap based lubricant use solution to the exterior of the P.E.T. container, wherein the pH of the concentrate from which the use solution is made is in the range of 9 to 10.5, the use solution comprising a stress cracking inhibitor which is a compound of one or more of the alkyl aryl phosphate ester and alkyl phosphate ester singly or in combination. 
     
     
       12. The method of claim 11, wherein the stress cracking inhibitor, alkyl aryl phosphoric ester or alkyl phosphate ester, which also serves as emulsifying agent, is selected from the group consisting of polyoxyethylene decyl ether phosphate, polyoxyethylene nonylphenyl ether phosphate, polyoxyethylene dinonylphenyl ether phosphate, and mixtures thereof. 
     
     
       13. A method of inhibiting stress cracking on a poly(ethylene terephthalate) article, comprising the step of applying to said article a soap based composition consisting essentially of a free phosphoric acid or potassium salt of an alkyl aryl phosphate ester in the presence of an alkali metal hydroxide. 
     
     
       14. The method of claim 13, wherein the said alkyl aryl phosphate esters are selected from the group consisting of polyoxyethylene nonylphenyl ether phosphate, polyoxyethylene dinonylphenyl ether phosphate and mixtures thereof. 
     
     
       15. The method of claim 13 wherein the said alkyl aryl ether phosphates are of the formula:   R.sub.2 R.sub.3 --C.sub.6 H.sub.3 --O[--CH.sub.2 CH.sub.2 --O]n--P O.sub.3 X.sub.2                                                   (II)     in which R 2  is linear or branched saturated primary alkyl groups, containing 8 to 12 carbon atoms, R 3  is hydrogen, or linear or branched saturated primary alkyl groups containing 8 to 10 carbon atoms, X is hydrogen and/or an alkali metal, and n is an integer in the range from 4 to about 10.   
     
     
       16. A method of inhibiting stress cracking on a poly(ethylene terephalate) article comprising the step of applying to said article a soap based composition consisting essentially of a free phosphoric acid or potassium salt of an alkyl phosphate ester in the presence of an alkali metal hydroxide. 
     
     
       17. The method of claim 16, wherein the said alkyl phosphate ester is the polyoxyethylene decyl ether phosphate. 
     
     
       18. The method of claim 16 wherein the said alkyl ether phosphates are of the formula:   R.sub.1 --O--[CH.sub.2 CH.sub.2 --O]n--PO.sub.3 X.sub.2    (I)     in which R 1  is a linear or branched saturate primary alkyl group, C8 to C12, X is hydrogen and/or an alkali metal, and n is an integer in the range from about 3 to 10.   
     
     
       19. An aqueous conveyor lubricant concentrate composition for P.E.T. containers moving on a conveyor system comprising: (a) Water present in the amount between 32 to 70 percent, by weight, based on the total concentrate weight; and   (b) A fatty acid mixture of tall oil fatty acid present in an amount between 6 to 22 percent by weight of the total concentrate; and   (c) As stress crack inhibitors, polyoxyethylene dinonylphenyl ether phosphate, polyoxyethylene decyl ether phosphate and polyoxyethylene nonylphenyl ether phosphate, present in an amount between 0.5 to 9.0 percent, by weight, of the total concentrate; and   (d) As emulsifiers, polyoxyethylene decyl ether phosphate, polyoxyethylene dinonylphenyl ether phosphate, polyoxyethylene nonylphenyl ether phosphate, ethoxylated nonylphenol, ethoxylated dinonylphenol, and ethoxylated tridecyl alcohol, present in an amount between 0.5 to 12 percent, by weight, of the total concentrate; and   (e) Potassium hydroxide present in the amount of 2 to 10 percent, by weight, based on the total concentrate weight; and   (f) Sequestrant agent present in the amount between 6 to 15 based on the total concentrate weight; and   (g) Coupling/hydrotrope agent present in the amount between 3 to 27 percent based upon the total concentrate weight; and   (h) Optional inorganic phosphate present in the amount between 0.2 to 6 percent of the total concentrate weight.   
     
     
       20. In a process comprising lubricating continuous conveyors of P.E.T. vessels for containing food or beverages, the improvement wherein the lubricant concentrate used is an aqueous lubricant composition having a pH value in the range from about 9.0 to 10.5, and comprises 32 to 70 percent of water by weight of the total composition and: (a) From about 0.5 to 9.0 percent by weight of the total composition comprising at least one compound of the formulas (I) or (II):   R.sub.1 --O--[CH.sub.2 CH.sub.2 --O]n--PO.sub.3 X.sub.2    (I)     in which R 1  is a linear or branched saturate primary alkyl group, C8 to C12, X is hydrogen and/or an alkali metal, and n is an integer in the range from about 3 to 10:     R.sub.2 R.sub.3 --C.sub.6 H.sub.3 --O[--CH.sub.2 CH.sub.2 --O]n--P O.sub.3 X.sub.2                                                   (II)     in which R 2  is linear or branched saturated primary alkyl groups, containing 8 to 12 carbon atoms, R 3  is hydrogen, or linear or branched saturated primary alkyl groups containing 8 to 10 carbon atoms, X is hydrogen and/or an alkali metal, and n is an integer in the range from 4 to about 10 and     (b) From about 6 to 22 percent, by weight, of the total composition of molecules selected from the group of a long-chain fatty acid consisting of carboxylic acid having from about 12 to 22 carbon atoms in the alkyl portion thereof; and   (c) From about 0.5 to 12 percent of the emulsifying agent by weight of total composition; and   (d) From about 2 to 10 percent, of the saponifying agent by weight of total composition; and, optionally,   (e) Conventional sequestering agent, coupling/hydrotrope agent, optional inorganic phosphate, or mixtures thereof.